<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>流式布局</title>
    <style>
        .left {
            float: left;
            width: 100px;
            height: 200px;
            background: red;
        }

        .right {
            float: right;
            width: 200px;
            height: 200px;
            background: blue;
        }

        .main {
            margin-left: 120px;
            margin-right: 220px;
            height: 200px;
            background: green;
        }
        .container::after {
            content: "";
            display: table;
            clear: both;
        }

        /* .container {
            padding-left: 150px;
            padding-right: 190px;
        }

        .main {
            float: left;
            width: 100%;
            background: red;
        }

        .left {
            float: left;
            width: 190px;
            margin-left: -100%;
            position: relative;
            left: -150px;
            background: yellow;
        }

        .right {
            float: left;
            width: 190px;
            margin-left: -190px;
            position: relative;
            right: -190px;
            background: green;
        } */
    </style>
</head>

<body>
    <div class="container">
        <div class="main">111</div>
        <div class="left">222</div>
        <div class="right">333</div>
    </div>

</body>

</html>